Field of Invention
The present invention relates to the field of camera, and more particularly, to a camera module and manufacturing method thereof.
Description of Related Arts
Conventional camera module is made by independently producing each of the components and then assembling them by packaging. Specifically, a conventional camera module includes a circuit board, a photosensitive sensor, a frame, a set of resistance-capacitance components, and an optical lens. After the circuit board, the photosensitive sensor, the frame, the resistance-capacitance components, and the optical lens are respectively produced, the photosensitive sensor, the resistance-capacitance components, and the frame are respectively and spacedly adhered on the same side of the circuit board, wherein the photosensitive sensor is electrically connected to the circuit board by electrically conducting peripheral edges of the photosensitive sensor to the circuit board through one or more wires, made of conductive material such as gold or aluminum alloy, by means of a wire bonding technique. The optical lens is arranged to be positioned along a photosensitive path of the photosensitive sensor. In the horizontal direction of the camera module of the current art, safety distances are required to be reserved between both the resistance-capacitance component and the gold wire and the resistance-capacitance components and the frame. In the vertical direction of the camera module of the current art, a safety distance is also required to be reserved between the resistance-capacitance components and the frame. This conventional way of the camera module in current art results a larger size of the camera module in the height size, length size and width size, that makes the size of the camera module being difficult to satisfy the development trend of having lighter and thinner electronic devices in the recent years.
In order to solve this problem, camera module made based on the MOC (Molding On Chip) packaging technique is developed by the applicant, wherein the frame, the photosensitive sensor and the resistance-capacitance components are respectively adhered on the circuit board to form an integral structure. Since no safety distance is required to be reserved between the frame and the resistance-capacitance component, the sizes in height, width and length of the camera module can be reduced. Besides, the integrally connection of the photosensitive sensor, the resistance-capacitance component, the circuit board, and the frame of the camera module can reinforce the strength of the circuit board and thus also enhance the strength of the camera module. In particular, after the photosensitive sensor and the resistance-capacitance component are respectively attached on the circuit board, the circuit board is placed within a mold. Then, the upper part of the mold directly applies pressure on the peripheral edges of the photosensitive sensor so as to isolate the photosensitive area from the non-photosensitive area of the photosensitive sensor. By melting molding material to fill the mold, the molding material after solidification will enclose and wrap up all the resistance-capacitance components, boding wires between the photosensitive sensor and the circuit board and the non-photosensitive area of the photosensitive sensor, so as to combine the photosensitive sensor, the resistance-capacitance component, the circuit board, and the frame to an integral structure. Such manufacturing process and structure of the camera module however have the following problems.
First, normally in order to enhance the photosensitivity of the photosensitive sensor, each pixel element of the photosensitive sensor has a micron level microlens. For example, a 13-million-pixel photosensitive sensor has 13 million microlenses respectively matching each of the pixel element. The matching relationships between the microlens and the pixel elements include size, position, and suitable structure. Because the microlenses are micron level lenses, they are extremely vulnerable, especially under the high temperature and high pressure circumstance in the mold. Damages of the microlens are the mainly breakdowns, distortions, or dislocations of the microlens. Once any one of the microlenses of the photosensitive sensor is damaged, the imaging quality of the camera module would certainly be affected.
Next, since the circuit board and while the photosensitive sensor is attached on the circuit board would have certain tolerances, a tilt would occur after the photosensitive sensor was attached on the circuit board. As the mold presses on the peripheral edges of the photosensitive sensor, gaps will be formed between the mold and the peripheral edges of the photosensitive sensor. Therefore, when the molding material is filled into the mold to form the frame that integrally combines the circuit board, the photosensitive sensor, and the resistance-capacitance components with the molding material, the molding material will leak out through the gap formed between the mold and the photosensitive sensor. The leaked molding material forms burrs at the edges of the frame that shelter the photosensitive path of the photosensitive sensor, that affects the imaging quality of the camera module. In addition, the molding material leaked from the gaps formed between the mold and the photosensitive sensor is in fluid form that has a higher temperature, so that once the molding material flows to the photosensitive area of the photosensitive area, the molding material with high temperature would cause damages to the photosensitive area of the photosensitive sensor and the microlenses of the photosensitive area of the photosensitive sensor.